In efforts to achieve ever greater performance in interactions between different electronic devices connected by lengthy conductors made up of printed circuit board (PCB) traces and/or cable wires, such as computer systems and peripheral devices (e.g., printers, scanners, cameras, disk drives, etc.), the rates at which commands and/or data are transferred between such electronics systems through such lengthy conductors have continued to be increased. It is typical for such external cables to be of considerable length to suit the convenience of users of such electronic devices by allowing such users the flexibility to place such electronic devices some distance apart from each other. Indeed, a length of approximately six feet or two meters has become quite commonplace for such external cables. It is also typical for electronic devices to have connectors positioned on the exterior of electronic devices at locations about the exterior of such electronic devices to suit either the convenience or aesthetic concerns of users, and this often results in the use of lengthy PCB traces to couple those connectors to the necessary circuitry within those electronic devices. However, such lengthy cable wires and/or PCB traces present lengthy conductors that increase capacitance levels and frequency-dependent signal loss, thereby slowing down the rate at which changes in voltage levels that are meant to signal changes in binary values are able to propagate from one end of such lengthy conductors to the other. In earlier years, with slower data transfer rates, this slower rate of signal propagation could be largely ignored, since there was plenty of time available for such propagation to occur such that the entire conductor would achieve the new desired voltage level with plenty of time to spare before the new voltage level would be read by a device receiving that signal.
However, in the current day, data transfer rates have already become high enough that the amounts of time required for such propagations of changes in signals across such a lengthy conductor have now become significant quantities of time that can no longer be ignored and must, therefore, be reduced to allow data transfer rates to increase further. Various techniques have already been tried in an effort to address this issue, including the use of lower voltage swings (i.e., decreasing the difference between voltage levels of high and low states) and differential signaling. Unfortunately, the need for the voltage level of the high state to be distinguishable from the voltage level of the low state by receiving circuitry limits the degree to which the difference between those two voltage levels may be reduced.
Therefore, there continues to be a need for a way to transfer data between electronic devices connected through lengthy conductors that further counteracts the delays in the propagation of changes in signals induced by the added signal loss arising from such conductor lengths.